It is known that reducing the amount of drag which acts on a vehicle improves the fuel consumption of the vehicle. Reducing the drag which acts on haulage vehicles, such as trucks, is therefore particularly desirable since any saving in fuel, as a consequence of the improved fuel consumption, translates into a saving in haulage costs.
It is known that the amount of drag which acts on a vehicle can be reduced by streamlining a vehicle. To this end, various aerodynamic devices such as fairings and deflectors have been fixed to trucks. Examples of such devices are described in U.S. Pat. No. 4,624,497, U.S. Pat. No. 4,750,772 and WO 2006091147.
However, trucks are generally used to carry bulky cargos. Consequently, the extent to which a truck can be streamlined is limited. Furthermore, known aerodynamic devices are designed to be most effective when a truck is operating in still air or a direct headwind/tailwind. Consequently, any benefits provided by the streamlining devices are often lost when the truck is operated in a crosswind.